Linear index for rectilinear driving device

Abstract

A linear index for a rectilinear driving device. This linear index divides a total driving section of the rectilinear driving device at regular intervals and forcibly drives and stops this device step by step using an electric signal, thus to precisely stop the piston of the cylinder at several random positions. The linear index comprises a linear index bar having a plurality of index protrusions spaced out at regular intervals, an index unit for moving the linear index bar step by step by 1/2 of the interval between the index protrusions in accordance with electric control signals, a main pneumatic cylinder connected to the linear index bar through a vertical connection member in order to cooperate with the linear index bar, and a programmable logic controller for outputting the electric control signals to the index unit. The index unit includes a pair of index parts oppositely positioned such that they face each other with interposition of the linear index bar therebetween, a projection extending from each of the index parts toward the linear index bar and a pair of proximity sensors mounted on opposed sides of the projection.